/* Estilos generales */
body {
    margin: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #7bb661, #d0e8c9);
    color: #3a4d2f;
    overflow-x: hidden;
}

/* Contenedor de partículas */
.particles {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    pointer-events: none;
    z-index: 0;
}

/* Tarjeta principal */
.card {
    position: relative;
    max-width: 420px;
    margin: 80px auto;
    background: #f5f9f0cc;
    border-radius: 20px;
    box-shadow: 0 8px 30px rgba(0,0,0,0.1);
    padding: 30px 25px;
    z-index: 1;
}

.header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: #43652b;
    text-align: center;
    text-transform: uppercase;
}

.header h2 {
    margin: 5px 0 10px 0;
    font-size: 2.2rem;
    font-weight: 900;
    color: #a6c48a;
    text-align: center;
}

.date {
    font-size: 1.1rem;
    text-align: center;
    color: #4a6837;
    margin-bottom: 20px;
}

.photo-frame {
    width: 200px;
    height: 200px;
    margin: 0 auto 20px auto;
    border-radius: 50%;
    overflow: hidden;
    border: 5px solid #a6c48a;
    box-shadow: 0 0 15px #92b36b88;
}

.photo-frame img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.message {
    font-size: 1.2rem;
    line-height: 1.5;
    text-align: center;
    margin-bottom: 25px;
    color: #3a4d2f;
}

.btn {
    display: block;
    margin: 0 auto 25px auto;
    background: #92b36b;
    color: #f5f9f0;
    border: none;
    padding: 12px 30px;
    border-radius: 30px;
    font-weight: 700;
    font-size: 1.2rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
    box-shadow: 0 5px 10px rgba(146,179,107,0.5);
}

.btn:hover {
    background: #7bb661;
    box-shadow: 0 6px 15px rgba(123,182,97,0.8);
}

.signature {
    font-style: italic;
    text-align: center;
    color: #6b8742;
    font-weight: 600;
}

/* Modal Carta */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(55, 85, 35, 0.75);
    backdrop-filter: blur(6px);
    z-index: 10;
    overflow-y: auto;
    padding: 40px 20px;
}

.modal.show {
    display: block;
}

.modal-content {
    background: #f5f9f0;
    max-width: 600px;
    margin: 40px auto;
    padding: 30px 30px 40px;
    border-radius: 20px;
    box-shadow: 0 10px 35px rgba(55, 85, 35, 0.4);
    color: #2f4620;
    font-size: 1.1rem;
    line-height: 1.6;
}

.letter-title {
    font-size: 2rem;
    font-weight: 900;
    text-align: center;
    margin-bottom: 20px;
    color: #43652b;
}

.letter-content {
    white-space: pre-wrap;
    margin-bottom: 30px;
}

.letter-signature {
    font-weight: 700;
    text-align: right;
    font-style: italic;
    font-size: 1.2rem;
    color: #5a7630;
}

/* Botón cerrar */
.close-btn {
    position: absolute;
    top: 15px;
    right: 25px;
    font-size: 2.4rem;
    color: #a6c48a;
    cursor: pointer;
    font-weight: 900;
}

.close-btn:hover {
    color: #7bb661;
}